No one was injured in the blaze, which was reported shortly after 4 p.m. The ambulance was fully engulfed in flames by the time firefighters arrived, said city spokeswoman Monica Zech. Witnesses reported hearing oxygen tanks inside the rig explode as the flames reached them.

The fire were out about ten minutes later.

The vehicle, owned by ER Ambulance Service, was not occupied, Zech said.

The west side of the mall entrance was closed for about 30 minutes while firefighters mopped up the scene. The cause of the blaze is under investigation.